Traditional computing devices rely on physical instrumentation such as a mouse, keyboard, or touch screen to receive user input. A projection-based user interface enables the user to interact with a virtual input device projected onto a surface. For example, a virtual keyboard can be projected onto a tabletop surface and the user can select keys on the virtual keyboard by touching the surface over which the virtual keyboard is being projected. To detect user inputs, a depth sensor can be used to determine the position of a user's fingers relative to the projected display. Receiving user inputs in this way provides a more flexible input mechanism that does not require any surface instrumentation.
The same numbers are used throughout the disclosure and the figures to reference like components and features. Numbers in the 100 series refer to features originally found in FIG. 1; numbers in the 200 series refer to features originally found in FIG. 2; and so on.